Can VGA output do progressive scan?

Discussion in 'Mac Basics and Help' started by Dabisu, Dec 6, 2006.

  1. Dabisu macrumors member

    Joined:
    Jun 8, 2006
    #1
    Hi, I'm purchasing an HDTV, and I don't have much money to spend but I do have an old computer with a DVD drive and this LCD HDTV has VGA input. So I was figuring I can use my PC for a dvd player until I get some more cash. This TV can display 720p and I'd like to watch movies in progressive scan, so is that possible with VGA? Would it be primarily the video card that determines the output and progressive scan? What are the limitations to VGA on an HDTV?

    I know this is a Mac forum, but I use my iMac instead of my pc, but everyone on here has been very helpful. Also, if I wanted to control my PC via my Mac for media viewing, would a program like VNC be sufficient or is there a better program specifically for that, because I did see a program that did that with Mac Minis but not sure about PCs.
     
  2. glennp macrumors member

    Joined:
    Aug 7, 2006
    Location:
    Washington, DC
    #2
    There's a couple things involved here.

    1) Computer video is almost always non-interlaced (aka progressive) unless you've got an old Commodore 64 or something. By connecting your computer to the TV, you'll be watching a progressive picture.

    2) However, the resolution (or how the picture fills the screen) is a different matter. The VGA input is an analog input into your TV and it will probably handle multiple resolutions. Standard VGA resolution is 640x480 which will not fill your HDTV (unless the image is stretched horizontally, distorting the picture). When you connect the computer to the TV, try to use a widescreen resolution (something like 1280x720) to maximize your screen's real estate. Which resolutions you'll be able to use are dependent on the video card and TV. You generally want to get something as close as possible to the native resolution of the TV for best effect.

    3) Standard DVDs are 480p and then that picture is scaled to fit the TV screen. The question will become does a dedicated DVD player/TV combo produce a better scaled picture or will a computer stretching the 480p picture to 1280x720 produce a better picture?

    Definitely hook up the computer to your TV but for best DVD performance, get a dedicated DVD player with component or DVI/HDMI outputs.
     
  3. Dabisu thread starter macrumors member

    Joined:
    Jun 8, 2006
    #3
    Hey thanks for all the info! Now I really want to get a dedicated DVD player so I can enjoy my new TV much better.
     
  4. mkrishnan Moderator emeritus

    mkrishnan

    Joined:
    Jan 9, 2004
    Location:
    Grand Rapids, MI, USA
    #4
    The best option is to find out the native resolution of the TV and then try to get your video card to display it. As stated, TVs are mostly 1280x720 or 1366x768 (what mine is) or 1920x1080 I think, if you get the nicest ones. So if you can do that actual native resolution, this is the best bet. It will not be interlaced at that resolution. Besides which, LCD TVs do not have the capability to interlace anyways... even interlaced hi-def resolutions like 1080i have to be converted to progressive resolutions for an LCD....
     
  5. Dabisu thread starter macrumors member

    Joined:
    Jun 8, 2006
    #5
    My video card I have in there could go way up to 2048 x 1536. I belive that is quite a bit over what my new HDTV will actually be able to display. I never worked in anything past 1600 x 1200 because my monitor couldn't support anything higher. I will try setting my PC to the native resolution of my HDTV when I get it, however, if I set my resolution on my PC higher than that capable of the HDTV will it still display and could that ever match or exceed the quality of a dedicated DVD player?
     
  6. mkrishnan Moderator emeritus

    mkrishnan

    Joined:
    Jan 9, 2004
    Location:
    Grand Rapids, MI, USA
    #6
    How this is handled depends somewhat on the TV in question... I think most TVs will adapt if they see a 1080 signal for instance and don't have that many pixels. Not so sure if you go higher than that.

    As far as a dedicated DVD player, unless it's a high-def standard like Blu-ray, yes, the computer puts out much more resolution than regular DVDs. But you have to find video source that's at a higher resolution. I think that both regular DVDs and iTunes store movies are in the rough range of 480p...
     
  7. Dabisu thread starter macrumors member

    Joined:
    Jun 8, 2006
    #7
    Well I was looking at DVD players that upscale up to 720p, 1080i and had component and HDMI output. I should've made that clearer, if I don't have to spend the extra money and get better picture than an upscaling DVD player then I'll just use my pc. However it is big and loud and no remote... >_<
     
  8. Anonymous Freak macrumors 601

    Anonymous Freak

    Joined:
    Dec 12, 2002
    Location:
    Cascadia
    #8
    Your TV probably has a resolution of 1366x768, which means that upsampling to 1080p won't matter, since the TV can't show that full resolution, anyway. In that case, if it has VGA input, plug in the VGA cable, and set your computer resolution to 1366x768 (if it supports it, 1280x720 if it doesn't,) and you will get the 'full' quality. Note that if it's a PC, it also depends on the quality of the DVD player software on the PC. If it can't upsample very well, then it doesn't matter. Also, if the source DVD isn't progressively encoded, it won't matter, since the PC will have to 'de-interlace' the source, which does mean it is slightly reduced quality. (I've found that watching interlaced-source DVDs looks better on a high end 'standard definition' TV than it does on a computer screen, since it was meant to be viewed interlaced.)
     

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